1. Field of the Invention
The present invention relates generally to the field of switchgear for electrical power distribution and more particularly to an arrangement and method for improving the arc-resistant features and capabilities of switchgear that is applicable either during fabrication or as a retrofit to existing equipment in the field.
2. Description of the Related Art
Various types of arc-resistant switchgear are known in the prior art, for example, as shown in U.S. Pat. Nos. 6,100,778, 5,574,624, 5,689,097, 5,710,402, 5,892,195 and 5,414,584. These typically include pressure relief arrangements that quickly relieve internal pressures developed during any arcing ensuing as the result of an internal short circuit or the like, i.e. a fault condition established within the switchgear. However, during the fault condition, the switchgear must also withstand the effects of the intense internal temperatures and pressures prior to and after the pressure relief features are operable. For example, it is desirable that all venting of the internal pressure occur via the pressure relief features and that the access doors and seals remain intact. Arc-resistant switchgear is the subject of various standards, e.g. Canadian standard EEMAC G14.1. Such standards describe various tests and characteristics that are desirable for such equipment.
While the arrangements of the prior art may be generally suitable for their intended uses, it would be desirable to provide arc-resistant switchgear with increased capabilities.